This is for a scooter that I have playing with and modifying for way too long. It has gone through many different forms of which I will show some pictures of here. I tinkered with some pocketbikes for a little while but I always had a soft spot for upright scooters which is what lead me to this.

As of the making of this post it's finally running again with it being back at using a Cag engine of which I am experimenting with and with to use it as a test bed to set up an electronic ignition that can also be used on my other engines.

If someone could tell me if there is a way to have the attached images displayed in the main post instead of just at the bottom then that would be appreciated.

DISCLAIMER: Although I often come across like I know what I am doing and sometimes I even do, but instead I am often working with ideas that I think are right but can be potentially flawed. This is mostly the case with my custom engine work and while I have done a decent amount of reading there is sometimes false or gaps in my information. I am very open to suggestions and corrections in anything I state.

Now that aside what might be the single most drawn out worklog on here.

Pic 1 - Bare frame: This is what I started with, it's a childrens scooter, I believe it originally used 16" BMX wheels. I am not sure on the exact date but it was likely back in 2003 some time. At that point I had much more limited skills, knowledge and most of access to equipment.

This ran alright and I was going to make some nice custom parts for it but a deal came up for a Blata rep engine- it was the aircooled 40cc "F1" engine. Apparently rated at 7Hp with the original carb and 9Hp with the 19mm carb I was running.

Pic 1 + 2: Modding the frame to suit the new engine

Pic 3: Further frame work on the engine mounting.

Pic 4: The original mounting of the frame complete. I wasn't happy with how this ended up which will leads to the next post.

At the time I had some doubts about the quoted power figure but wow did I get a wake up call. Initially the slightest bit too much throttle would cause it to do a wheel stand and throw me off. This would happen up or down a hill all the same. I changed from a 6 to a 7 tooth pinion which helped keep the front wheel down but it was still quite scary for me to try and control. If I leaned back it would want to wheel stand, if I leaned forward I couldn't control it properly with the balance and steering. To give an example I own a street luge and I found the Luge quite pleasant compared to how much on edge this made me feel. It was amazing and regardless how dangerous it was it sure loved it.

To optimistically attempt to control this better I modified the frame further.

Pic 1- Base: The frame was extended and to get some extra rigidity x3 Cro-Mo (4130) pipes were used which made a noticeable difference.

Pic 2 + 3: The rear part of the frame after being modded. The base plate was yet to be extended.

I don't believe I have a photo of how it was after the final assembly.

A little while after this point the ignition coil failed as so many chinese coils do. I couldn't find a replacement anywhere and sadly as a result this was put aside and ignored for something like 10 years under my house rusting away.

A little over a year ago I decided that even though it would be a big downgrade going back to a Cag engine it would at least run again and give me something to use. And as such this now rusty old scooter was pulled back out and prepared for a downgrade.

Pic 1 - Initial engine mounting: The time this has been sitting around is clearly visible here. In this photo I had fitted the new engine mounting plate has been fitted.

At this stage I was going for the same type of design again but I started to think about how a stand up scooter really isn't practical or comfortable in any sense. I had a friend who had a Go-Ped riot which I sat on and found it to be really comfortable, it was very likely this that caused me to change my plan. I had always suspected that my previous geometry was crap so this time I decided to use something else as a reference. With my tape measure and digital angle gauge I worked out all the basic dimensions of the Go-Ped and from then worked out a plan to make something to match those numbers.

Pic 1: With the original deck temporarily in place the following was fitted: angled lower tubes, RHS cross bar foot pegs, seat pole and the headset tube was shortened.

At this stage the only thing left from the original scooter is 2/3 of the head tube and a small part of the original fork in it's middle section. For some reason I didn't take any more progress photos after this so it's going to be a jump to the near end.

This is how this scooter is as it is right now. It needs to have the kill-switch fitted and likely some other small jobs done but regardless it finally runs again. I was only able to use it for a short time but in that time the stability felt really good, it was very comfortable to use and it performed better than I expected.

I did make some big compromises when making this as I didn't want to fall into the same old trap for me of where I try and make it the best I possibly can and it ends up taking so long that I lose interest or give up. I figure it's better to have some a bit crude than nothing at all.

I also have various photos of internal engine work, other information and engine plans to share but it's getting late over here so I am going to leave it for now and come back.

Seeings I'm a pretty inquisitive guy I have to ask one main question...

What made you want to go with a reed ported engine for a scooter...?

Mainly what I'm asking is if the scooter is for cruising ,racing or a lil of both...

Reason being is that I had built a scooter with a reed ported engine with CVT transmission and found that I was always fiddling with the reeds and trying to get a combo going that would add longevity to the reeds to no avail...

If I used the scooter for a 10 min blast up to the corner and back it was good....when I rose it 5 miles to my storage unit it would run crappy all the way home if I didn't waste my time flipping the reeds...

Piston ported engines are way more suited for applications where it's gonna be held WOT for periods of 2 miles or more....

The piston ported engine with the full circle crank mod was a sikk revved with sweet lower power and a vicious midrange punch....

EPR: thanks, it's been a long while in the works. Now hopefully on top of being nice to use I will also gain some understanding from doing some experimenting with this. The biggest priority at the moment is doing the last minor steps and then just going out and using it. Doesn't matter where so long as it takes me away from home as I really need a change of scenery.

Mrkitty: Nice one, that looks like it would be a blast to use.

Cam2: I initially used one of these engines due to the fact that at the time they were readily available, good value for money, easy to work on, very easy & cheap to source spares for, I had some knowledge on them, were compact and had a centrifugal clutch. As for why I decided to go back to one of these engines, a bit over a year back I figured it was the quickest way out of any option to have my scooter running again and I had lots of parts still.

Now for what might be my most ignorant question yet- can you give some examples of what might of been a good choices for piston ported engines that have centrifugal clutches? Were you thinking along the lines of sourcing a 50cc chainsaw engine?

As for what I want to use it for- I don't want to race, nor use it on the streets. I am going to do mixed riding from gravel paths, concrete flats and other locations. I know it might sound like a dumb idea as it's not really suited to some of the places that I plan to go. But the way I see it it's not like I have a whole lot on the line, I certainly won't be afraid to drop it should I happen to slip due to using small road tyres on a gravel path.

That's a new one to me with the reeds. What went wrong exactly with your reeds? Would they split? What material were yours made of?

One of the things I have been considering to do is to adapt a reed block I made from way back when I was first learning how to use a milling machine. It suits the Blata reed assembly, pics attached. It looks so over the top because I had much more time and energy back then and I was also excited by being able to do milling for the first time, it was fun to machine up and good practice. To make it suit my current engine I would need to make a fairly simple adapter to go between this and the existing reed block mount. This is already half made so it would be quick and easy to finish it. From there I would also need to make an intake manifold which would be a little more annoying but still not too bad to do.

My goal is still to experiment with an electronic CDI ignition which I will hopefully then let me be able to go on to adapt it to use on my Blata Rep engine. This will let my other custom motorbike finally run. So while I might have lots of ideas of what I could do to an engine in the scooter right now I want to balance it so that I don't get too distracted and spend too much time long term on it. Instinctively I want to try lots of different ideas but I need to remind myself to not get completely fixated on it.

EPR: thanks, it's been a long while in the works. Now hopefully on top of being nice to use I will also gain some understanding from doing some experimenting with this. The biggest priority at the moment is doing the last minor steps and then just going out and using it. Doesn't matter where so long as it takes me away from home as I really need a change of scenery.

Mrkitty: Nice one, that looks like it would be a blast to use.

Cam2: I initially used one of these engines due to the fact that at the time they were readily available, good value for money, easy to work on, very easy & cheap to source spares for, I had some knowledge on them, were compact and had a centrifugal clutch. As for why I decided to go back to one of these engines, a bit over a year back I figured it was the quickest way out of any option to have my scooter running again and I had lots of parts still.

Now for what might be my most ignorant question yet- can you give some examples of what might of been a good choices for piston ported engines that have centrifugal clutches? Were you thinking along the lines of sourcing a 50cc chainsaw engine?

As for what I want to use it for- I don't want to race, nor use it on the streets. I am going to do mixed riding from gravel paths, concrete flats and other locations. I know it might sound like a dumb idea as it's not really suited to some of the places that I plan to go. But the way I see it it's not like I have a whole lot on the line, I certainly won't be afraid to drop it should I happen to slip due to using small road tyres on a gravel path.

That's a new one to me with the reeds. What went wrong exactly with your reeds? Would they split? What material were yours made of?

One of the things I have been considering to do is to adapt a reed block I made from way back when I was first learning how to use a milling machine. It suits the Blata reed assembly, pics attached. It looks so over the top because I had much more time and energy back then and I was also excited by being able to do milling for the first time, it was fun to machine up and good practice. To make it suit my current engine I would need to make a fairly simple adapter to go between this and the existing reed block mount. This is already half made so it would be quick and easy to finish it. From there I would also need to make an intake manifold which would be a little more annoying but still not too bad to do.

My goal is still to experiment with an electronic CDI ignition which I will hopefully then let me be able to go on to adapt it to use on my Blata Rep engine. This will let my other custom motorbike finally run. So while I might have lots of ideas of what I could do to an engine in the scooter right now I want to balance it so that I don't get too distracted and spend too much time long term on it. Instinctively I want to try lots of different ideas but I need to remind myself to not get completely fixated on it.

Currently it's the middle of winter over here and it's been raining very regularly so I have not been able to use my scooter.

Regardless I did a little bit of work on a concept today. I am using one of the 14mm carbs that are apparently a copy of a Dell'Orto. Also known as a "HP carb". I have been thinking for a while that the harsh transition for the air going into the throat can't be good and about the possibility of fitting a velocity stack.

Removing the choke arm and spring leaves a handy M5 threaded hole as per Pic-1. I figure the engine is very easy to start as is so it shouldn't be an issue. In the quick design I came up with it the velocity stack sits against the various faces and has clearance cut-outs where required, such as whatever that lump is to the middle left of the inside face. I also put in an additional hole to feed the idle control circuit, this is the very small hole directly under the main opening.

After putting in the basic dimensions I then designed it in Solidworks to have a true parabolic transition. Once done I exported it to my 3D printing software, set up the print, saved the setup to a SD card and then gave it to my 3D printer.

Predictably the carb isn't properly concentric but it was close enough such that with some light filing it ended up lining up and fitting quite well. The filter fits into place much the same as it normally would. The overly bright light blue colour just happens to be what's currently loaded in the 3D printer.

When I get a chance I will try this out, conveniently this is very quick and easy to fit and remove as required. it could well be that I am completely misunderstanding something fundamental to the function of the carb that makes this a flawed concept. I don't know, my knowledge and preferences are only to do with fuel injection so this is something new for me.

Something along those lines was my plan all along. If this works out then I shall make some small tweaks to the file to make it fit better. From there I am happy to share it to whoever wants it. I have the option of putting it thingiverse, emailing it to people or I can even use a a hidden link to host it my businesses website. I have a lot of bandwidth available as part of my hosting package so even large files are no problem.

It's also quite cheap for me to print. The printing was also didn't take too long with it being under 2 hours. But that was with a course setting and it made completely solid. I could do it again with it partially hollow, a 3 layer thick wall and a finer layer height. A much more subtle colour would be nice too, I have a silver material which looks nice.

Outstanding job, been wanting to make a V-stack for the 14mm SHA carb for 10 years. The Polini/14mm Dell has a V-stack that fits inside the stock air filter.
Have a 3D printer helps a lot. Ever think about selling them??

EPR: 3D printers can indeed make things simple. It's unusual for me to use it for any kind of part that's for actual final use. Up until now it has almost completely been used for parts development / test fitting only. I had didn't have any plans to sell them as I am short on time and energy as it is but the possibility is there if it's on a low volume. I already have an online store for auto parts and I send at least half of my products out of the country so it would be very quick and easy to make a listing for these.

Cam2: Even after taking my carb apart into pieces and once again thinking about how it all works I still don't follow what you mean. The bottom of the slide is flat so I don't see which cutaway height you are referring to. But I have yet to read up on doing carb tuning so if that will give me the answer then I don't want to trouble you with more of an explanation.

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